Process of preparing curable compositions and compositions therefrom

ABSTRACT

The invention relates to a curable composition and a process of preparing the curable composition. The process comprises (a) forming an oligomer from oligomerization of a mixture of a monomer A having a functional group and a monomer B at a temperature in the range of from 150° C. to 650° C., a pressure in the range of from 3 MPa to 35 MPa and the pressure is high enough to maintain the reaction mixture in a fluid state and a residence time in the range of from 0.1 second to 4 minutes; and (b) reacting a modifier having at least one reactive moiety with the oligomer through a reaction between the reactive moiety of the modifier and the functional group of the monomer A in the oligomer, and the modifier further comprises a curable group.

This application is a continuation-in-part of U S. application Ser. No.09/212,038, filed Dec. 15, 1998, a non-provisional application which:

has priority from provisional U.S. application Ser. No. 60/077,059,filed Mar. 6, 1998;

is a continuation-in-part of U.S. application Ser. No. 09/034,924, filedMar. 5, 1998, and now abandoned, which is a continuation of U.S.applcation Ser. No. 08/467,685, filed Jun. 5, 1995, and now abandoned,which is a divisional of U.S. application Ser. No. 08/258,300, filedJun. 13, 1994, and now abandoned; and

is a continuation-in-part of U.S. application Ser. No. 09/047,547, filedMar. 25, 1998, a non-provisional application having priority fromprovisional U.S. application Ser. No. 60/042,725, filed Apr. 8, 1997.

The present invention relates to a process of preparing curablecompositions and compositions therefrom.

Oligomers, polymers with low Dp (degree of polymerization), of acrylateor methacrylate unit-containing backbones are of commercial interest andhave industrial uses for many different applications, such as adhesives,inks, coatings, films, and others. A suitable low Dp value will providea material with a molecular weight high enough for reduced toxicity, yetlow enough for low viscosity. However, production of such oligomers hasproven to be difficult and is frequently carried out by cumbersomeand/or not very selective processes. It becomes even more difficult if acrosslinkable or curable oligomer composition is desired for theapplications. This is because crosslinking or curing property typicallyrequires the presence of additional reactive pendant groups in theoligomers. Such reactive pendant groups may be partially orsubstantially eliminated or reacted away by unintended side reactions orpremature crosslinking reactions during the oligomerization reaction.

Several approaches have been tried and used to effect production of sucholigomers. For example, one approach uses chain transfer agents tocontrol Dp. As a result of the chain transfer chemistry involved, onechain transfer agent is incorporated into each backbone structure of theoligomers. This makes the oligomer property much less uniform and harderto control. In addition, the most commonly used chain transfer agentsare mercaptans. Due to their odors and chemical properties, it becomesincreasingly more difficult socially and less acceptable environmentallyto use such sulfur-based materials. Other common chain transfer agentssuch as hypophosphites, bisulfites and alcohols would also impartadditional functionalities into the oligomers. Such additionalfunctionalities may not be compatible with other ingredients in aformulated product or suitable for the intended applications. Removal ofthe additional functionality from the resultant oligomers may bedifficult and/or expensive.

Another approach calls for the use of large amounts of initiators orcatalysts. This approach adds raw material cost to oligomer production.It also may result in undesirable oligomer chain degradations,branching, and unintended or premature crosslinking of the product priorto use. In addition, any residual initiators or catalysts in the productmay have to be removed before the product can be used for manyapplications to avoid compatibility or contamination problems.

U.S. Pat. No. 4,356,288, discloses the preparation ofterminally-unsaturated oligomers with a Dp in the range of from about 6to about 30 from esters of acrylic acid by an anionic polymerizationreaction carried out in the presence of a catalytic amount of analkoxide anion. Alkoxide anions are known to be sensitive to water.Accordingly, the method is often adversely affected by the presence ofmoisture, resulting in lower yield and/or lower uniformity of theoligomer product.

Another patent, U.S. Pat. No. 5,710,227, discloses a high temperature,continuous polymerization process for preparing terminally unsaturatedoligomers which are formed from acrylic acid and its salts, and acrylicacid and its salts with other ethylenically unsaturated monomers. Thehigh temperature, continuous polymerization process solves many of theproblems associated with previously known methods for preparingterminally-unsaturated oligomers formed from acrylic acid. However, theneat form of many of the acrylic acid products are solid at roomtemperature and, thus, requiring either heating and/or the addition of asolvent to handle and use the products.

U.S. Pat. No. 5,484,850 discloses copolymer compositions which arecrosslinkable by a free radical method and have a Mn from 1500 to 6000and a polydispersity of 1 to 4. Copolymer A is composed of from 50 to 85mol % of a monomer (a1) containing methacryloyl group; from 15 mol % to50 mol % of another monomer (a2) capable of undergoing free-radicalpolymerization; and from 5 mol % to 50 mol % of the total amount of themonomers (a1) and (a2) being monomers (a3) which carry functional groupsselected from the group consisting of hydroxy, carboxyamido, amino,carbonyl, isocyanate, carboxyl and epoxy, the functional groups beingcapable of undergoing a condensation or addition reaction. Thepolymerization is carried out at a temperature from 140 to 210° C. andwith an average residence time of from 2 minutes to 90 minutes.Copolymer A reacts with an olefinically unsaturated monomer B whichcarries a functional group which is complementary to the functionalgroups of monomers (a3). The products are solids which tend to limittheir uses and processing options.

The present invention seeks to overcome the problems associated with thepreviously disclosed methods for preparing oligomers, particularlycurable or crosslinkable liquid oligomers, by providing anoligomerization process that produces curable oligomers with a low Dp,in the range of from 3 to 100, without the need of excessive amounts ofinitiators. The curable oligomer products are in liquid form and may beterminally unsaturated. The crosslinkable or curable functionality isincorporated into the oligomer by a reaction after the oligomerization—apost-oligomerization reaction—between the oligomer or altered oligomerwith a modifier which contains a crosslinkable/curable functional group.The present invention also provides curable oligomer compositionsprepared according to the disclosed process. Furthermore, the inventionprovides curable oligomer compositions which are substantially free ofmetals, salts and/or surfactant contaminants. The product from thepresent invention is useful for a number of applications, such as films,markings, coatings, paints, adhesives, binders, inks and others.

More specifically, the present invention relates to a process ofpreparing a curable composition comprising forming an oligomer having aDp in the range of from 3 to 100 from oligomerization of a mixture whichcomprises a monomer A and a monomer B under a first condition, whereinthe monomer A has at least one functional group which either isgenerated after the oligomerization or is present in the monomer Abefore the oligomerization and remains substantially unreacted duringthe oligomerization; the oligomer has a first number of monomer unitsincorporated into its backbone; and wherein the first conditioncomprises a temperature in the range of from 150° C. to 650° C. and apressure in the range of from 3 MPa to 35 MPa which is sufficient tomaintain the mixture in a fluid state, and a residence time at thetemperature and the pressure in the range of from 0.1 second to 4minutes; and reacting a modifier having at least one reactive moietywith the oligomer through a reaction under a second condition betweenthe reactive moiety of the modifier and the functional group of themonomer A incorporated into the oligomer to produce the curablecomposition, wherein the modifier further comprises a curable groupselected from the group consisting of a carbon-carbon double bond, anoxygen-containing heterocyclic group and mixtures thereof, and thecurable group remains pendant in the curable composition andcrosslinkable after the reaction.

The term “oligomer” used herein means a polymer composition which has adegree of polymerization (Dp) in the range of from 3 to 100. Unlessotherwise specified in the present application, the term“polymerization” is used herein as a generic term and interchangeablywith the term “oligomerization.” An oligomer has a number of monomerunits incorporated into the backbone. Dp is determined as a monomer unitaverage number. Depending on the oligomerization reaction mechanism, theactual number of carbon atoms in a particular oligomer backbone may beof an even or an odd number, even though the carbon-carbon double bondsin the monomers have two carbons each. Since it is rare that all of theoligomer molecules have the same total number of monomer unitsincorporated into the backbone, there is usually a distribution ofvarious oligomers with either smaller and/or larger Dp than the rangeindicated and/or preferred in the application. This type of distributionis also known to exist in almost all polymers and it is commonlyreferred to as “polydispersity.” A preferred Dp for this invention is inthe range of from 5 to 50. A more preferred Dp is in the range of from 5to 20.

The present invention also relates to a curable composition,particularly by UV, visible light, electron beam methods, prepared by aprocess comprising forming an oligomer with a Dp in the range of from 3to 100 from oligomerization of a mixture which comprises a monomer A anda monomer B under a first condition, wherein the monomer A has at leastone functional group which either is generated after the oligomerizationor is present in the monomer A before the oligomerization and remainssubstantially unreacted during the oligomerization; wherein the monomerB is selected from the group consisting of ethylene, propylene, C₄ toC₁₀ α-olefins, butadiene, isoprene, styrene, substituted styrene, vinylester, vinyl ether, vinyl silane, vinyl halide, acrylic acid,methacrylic acid, crotonic acid, alkyl acrylate ester, alkylmethacrylate ester, alkyl crotonate ester, acrylamide, methacrylamide,N-substituted acrylamide, N-substituted methacrylamide and mixturesthereof; the oligomer has a first number of monomer units incorporatedinto its backbone; and wherein the first condition comprises atemperature in the range of from 150° C. to 650° C. and a pressure inthe range of from 3 MPa to 35 MPa which is sufficient to maintain themixture in a fluid state, and a residence time at the temperature andthe pressure in the range of from 0.1 second to 4 minutes; and reactinga modifier having at least one reactive moiety with the oligomer througha reaction under a second condition between the reactive moiety of themodifier and the functional group of the monomer A incorporated into theoligomer to produce the curable composition, wherein the modifierfurther comprises a curable group selected from the group consisting ofa carbon-carbon double bond, an oxygen-containing heterocyclic group andmixtures thereof, and the curable group remains pendant in the curablecomposition and crosslinkable after the reaction.

The word “pendant” means that a group, a functional group or a reactivemoiety, is not in the backbone structure itself of an oligomer orpolymer. A reaction of a pendant group for the present invention willnot cause any changes of the backbone structure itself. A pendant group,may be attached directly to a carbon in the backbone structure of theoligomer. Examples of this directly-attached type pendant groups include—OH or —OC(═O)(CH₃) group (from vinyl acetate monomer); and —COOH or—COO(R) group (from acrylates or methacrylates). Or, there may be otherintermediate chemical moieties or groups between the functional groupand the carbon atom in the backbone structure to server as “linkers.” Anexample of this type is the —OH group in 2-hydroxyethyl methacrylatewhen it is used as one of the monomers. There is a —CH₂CH₂— groupbetween the —OH group and the —C(═O)—O— group of the backbone structure.Other linker examples include O—CH₂CH₂_(n) where n is in the range of1 to 10. Others become clear from the rest of the description of thepresent invention. Pendant groups for this invention are generallyreactive, either they are suitable for attaching a crosslinkable orcurable group to the oligomers, or they are used for curing orcrosslinking. Curing and crosslinking are used herein interchangeably.

To facilitate understanding of the present invention, a general schemeis summarized below. It is used for illustration purposes only, notintended for limiting the scope of invention which is defined herein bythe specification and the claims. It is also understood that some of thesteps may be carried out simultaneously or sequentially.

monomer A+monomer B→oligomer [→post-oligomerization generation offunctional groups, optional]→reaction with a modifier to form a curablecomposition [→emulsion formation to form a curable formulation,optional]→curing or crosslinking.

In the instant invention, an oligomer is prepared by an oligomerizationreaction of a mixture which comprises a monomer A and a monomer B. Themixture may further comprise a solvent and other materials for a varietyof purposes such as catalysis or reaction mediation. The monomer A andthe monomer B preferably are different, but they may be the same incertain specific cases wherein the monomer A is produced by transformingthe monomer B incorporated in an oligomer after the oligomerizationreaction, as described below in more detail. The monomer A and themonomer B may be premixed, with or without a solvent, prior to theoligomerization, or they may be introduced separately into a reactionzone at a predetermined rate or manner. The latter typically requires amechanism to provide proper mixing. The mechanism can be static such asspecially designed inlets, nozzles, or mobile such as a mechanicalstirring device. For the present invention, it is preferred to have themonomers and optionally a solvent, if present, premixed before they arefed into the reactor.

For the present invention, the monomer A must have, in addition to apolymerizable or oligomerizable carbon-carbon double bond, a functionalgroup which does not participate in, or remains pendant or substantiallyunreacted during the oligomerization reaction. Such a functional groupmay be already present in the monomer A itself prior to theoligomerization or it may be generated after the oligomerization from a“monomer A equivalent.” After the functional group is generated, thereaction between the modifier through its reactive moiety and thefunctional group of the oligomer can be carried out to form the curablecomposition.

It is within the scope of the present invention to generate thefunctional group post-oligomerization from a “monomer A equivalent”,i.e. after the oligomerization is completed or substantially completed.This requires the use of a “monomer A equivalent” in the oligomerizationreaction and at least one additional conversion reaction to generate thedesired functional group. It is also possible to have the additionalconversion reaction and the oligomerization occur almost simultaneously.

A “monomer A equivalent” is an oligomerizable or polymerizable monomericcarbon-carbon-double-bond-containing compound which has another groupthat may be converted to produce the desired functional group after theoligomerization or polymerization is completed or substantiallycompleted during the oligomerization reaction. A “monomer A equivalent”may be the same as the monomer B used in the oligomerization reaction.

There may be various reasons and benefits for using a “monomer Aequivalent.” For example, vinyl alcohol does not have a chemicallystable monomeric form which can be easily used in an oligomerization orpolymerization reaction. Accordingly, vinyl acetate is used mostfrequently as vinyl alcohol's “equivalent” and the acetate group isconverted by hydrolysis to generate the desired hydroxy (OH) group afterthe oligomerization or polymerization reaction is completed. If desired,the acetate group can also be converted into an acrylate or methacrylategroup via a trans-esterification reaction or by hydrolysis followed bydirect esterification.

Following is another example of this type of post-oligomerizationgeneration of functional groups, particular pendant functional groups,where the “monomer A equivalent” is the same as the monomer B. Forinstance, a homo-oligomer of methyl acrylate may be partially orcompletely hydrolyzed to form carboxylic acid groups, i.e. —COOMe groupsare transformed into —COOH functional groups via hydrolysis. Suchfunctional groups then can be reacted with a modifier having a reactivemoiety such as glycidyl (meth)acrylate or hydroxyalkyl ester of acrylicor methacrylic acid to achieve the desired incorporation ofcrosslinkable or curable carbon-carbon double bonds. Another exampleinvolves a co-oligomer prepared from different esters of ethylenicallyunsaturated acids. A typical co-oligomer may be made from methylacrylate and n-butyl methacrylate. A post-oligomerization hydrolysisreaction will also produce —COOH groups. One advantage of such apost-oligomerization generation of functional groups is that thehydrolysis reaction can be controlled or adjusted to give the desiredlevel or amount of functional groups in the oligomer products. Becausedifferent monomer units in the oligomer structure usually have differenthydrolysis or trans-esterification rates, this method provides anotherway of controlling the incorporation of crosslinkable functionalities.Another type of post-oligomerization generation of functional groupsinvolves hydrolysis of pendant amide groups.

Many compounds are suitable for use as the monomer A in the presentinvention. The selection depends primarily on the monomer B used and thereactive moiety on the selected modifier. The monomer A must have atleast one functional group that exists after or does not substantiallyparticipate in the oligomerization reaction. General categories of suchfunctional groups include carbon-carbon double bond, halide,hydroxyalkyl, hydroxyaryl, carboxylic acid or ester, epoxy (oroxiranyl), oxetanyl, anhydride, alkylsiloxy, alkoxysilyl, and arylsiloxygroups. Groups like anhydride could be in a form incorporated throughthe carbon-carbon double bond of monomers like maleic anhydride,citraconic anhydride, and itaconic anhydride. It is understood that notall the disclosed functional groups can be used for all the differenttypes of oligomerization reactions. It is also understood that not allthe functional groups will react with all the reactive moieties of allmodifiers. For the present invention, there must be a reasonablereaction rate between the functional group and the reactive moiety undera second reaction condition, with or without a catalyst or reactionmediator. Chemical compatibility must also be satisfied. Specificlimitations on functional groups and reactive moieties are furtherdisclosed herein.

Examples of a monomer A suitable for the present invention include:acrylic acid, methacrylic acid, 1,3-butadiene, isoprene,4-vinylcyclohexene, allyl alcohol, allyl esters such as allyl acetate,allyl propionate, allyl acrylate, allyl methacrylate, allyl crotonate,vinyl acrylate, vinyl methacrylate, vinyl crotonate, vinyl chloride,vinyl bromide, vinylidene chloride, vinylidene fluoride, vinyl acetate,vinyl benzoate, norbornadiene, substituted norbornadienes,4-vinylcyclohexene oxide, glycidyl methacrylate, glycidyl acrylate,glycidyl crotonate, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate,4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropylmethacrylate, 4-hydroxybutyl methacrylate, acrolein, methacrolein,maleic anhydride, itaconic anhydride, citraconic anhydride,vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane,allyltrichlorosilane, allyltrimethoxysilane, allyltriethoxysilane,γ-methacryloxypropyltrimethoxysilane, and mixtures thereof.

Examples of a “monomer A equivalent” include vinyl acetate, vinyl halide(such as vinyl chloride, vinyl bromide, vinyl iodide, vinyl fluoride),vinylidene halide, allyl acetate, allyl propionate, methacrylonitrile,acrylonitrile, C₁-C₂₀ alkyl acrylate esters, C₁-C₂₀ alkyl methacrylateesters, C₁-C₂₀ alkyl crotonate esters, acrylamide and N-substitutedacrylamides such as N-methylacrylamide, methacrylamide and N-substitutedmethacrylamides such as N,N-dimethylmethacrylamide, and mixtures thereofThe corresponding functional groups generated are —OH (vinyl acetate andallyl acetate) and —COOH (others) respectively. Depending on the desiredproducts, certain monomer A such as maleic anhydride, itaconic anhydrideand citraconic anhydride also could serve as a “monomer A equivalent” toproduce dicarboxylic acid functional groups.

The monomer B is typically an ethylenically unsaturated monomer and itsderivatives thereof, such as olefins, styrenes, unsaturated carboxylicacids, esters and amides, vinyl esters, vinyl ethers, vinyl silanes, andmixtures thereof. A preferred monomer B comprises α,β-ethylenicallyunsaturated carboxylic acids, preferably acrylic acid and methacrylicacid, and their esters of linear or branched alcohols containing from 1to 20 carbons. Specific examples of monomer B include, but are notnecessarily limited to, ethylene, propylene, C₄-C₁₀ α-olefins,1,3-butadiene, isoprene, styrene, substituted styrenes such asp-methylstyrene, vinyl acetate, vinyl benzoate, vinyl chloride, vinylbromide, allyl acetate, methyl acrylate, methyl methacrylate, methylcrotonate, ethyl acrylate, ethyl methacrylate, ethyl crotonate, n-propylacrylate, n-propyl methacrylate, n-propyl crotonate, i-propyl acrylate,i-propyl methacrylate, i-propyl crotonate, n-butyl acrylate, n-butylmethacrylate, n-butyl crotonate, sec-butyl acrylate, sec-butylmethacrylate, sec-butyl crotonate, ethyl 4,4,4-trifluorocrotonate,2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexylcrotonate, acrylic acid, methacrylic acid, crotonic acid, acrylamide,methacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide,N,N-dimethylmethacrylamide, N,N-diethylmethacrylamide, ethyl vinylether, n-propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether,2-ethylhexylvinyl vinyl ether, 2-chloroethyl vinyl ether,2-aminoisobutyl vinyl ether, vinyltrimethylsiane and mixtures thereof.

Where the desired functional groups are already present in the monomer Aand remain substantially unreacted or pendant during and after theoligomerization, the molar ratio of the monomer A to monomer Bincorporated into the backbone of the oligomer produced is in the rangeof from 1:40 to 40:1, preferably in the range of from 1:20 to 20:1, mostpreferably in the range of from 1:5 to 5:1.

Where the functional groups are generated post-oligomerization from the“monomer A equivalent” incorporated into the oligomers, the ratio of thenumber of generated functional groups to the number of total monomerunits in the oligomer backbone is in the range of from 1:100 to 1:1. Itis also within the scope of the present invention if the “monomer Aequivalent” can be converted into more than one functional group, say znumber of groups, per monomer unit, the ratio could exceed 1:1 to ashigh as z:1. For example, if a monomer has a maleic anhydride groupwhich can be converted into two carboxylic functional group per monomerunit. The ratio could exceed 1:1 to 1.5:1 or to a maximum of 2:1.

The oligomerization reaction is carried out under a first conditionwhich comprises a temperature of at least 150° C., generally in therange from 150° C. to 650° C., preferably in the range of from 200° C.to 500° C., more preferably from 275° C. to 450° C. and a pressure inthe range of from 3 MPa to 35 MPa, preferably in the range of from 20MPa to 30 MPa. A preferred combination of temperature and pressure is inthe ranges of 150° C. to 400° C. and 16 MPa to 32 MPa respectively. Amore preferred combination of temperature and pressure is in the rangesof 180° C. to 350° C. and 20 MPa to 27 MPa respectively. At a giventemperature, it is most preferred to use a pressure high enough tomaintain the reaction mixture at the reaction temperature, with orwithout a solvent, in a fluid state—typically a liquid state or asupercritical fluid state. While a completely fluid state, either liquidor supercritical, is preferred, it is within the scope of the presentinvention that a substantially fluid state may be used. Compounds likewater, CO₂ or ethylene can be maintained as a supercritical fluid. Theresidence time is generally in the range of from 0.01 second to 20minutes, preferably in the range of from 0.1 second to 4 minutes, morepreferably in the range of from 0.5 second to 2 minutes, most preferablyin the range of 1 second to 1 minute. “Residence time” is defined hereinas the time the mixture comprising the monomers spends under the firstcondition for oligomerization.

A solvent or solvent mixture is not required, but may be used optionallyas a medium, for the oligomerization reaction. They are hereincollectively and interchangeably referred to as “solvent,” “solvents” or“solvent mixture.” A solvent selected for a particular oligomerizationreaction should neither interfere with the desired oligomerizationreaction nor react substantially with the functional group presenteither in any of the monomers or in the oligomer product. It ispreferable that a solvent can be easily separated or removed from thereaction products by such methods as distillation, phase separation, orevaporation. If a catalyst, mediator, or initiator is used, it ispreferred to have a solvent in which the catalyst or initiator issoluble in a usable amount. A mediator is a compound which, while notbeing able to catalyze the reaction, may nonetheless influence thereaction in a certain desirable manner. Examples of a solvent suitablefor use in an oligomerization reaction include, but are not necessarilylimited to, ethylene, pentane, hexane, heptane, octane, benzene,toluene, xylene(s), carbon dioxide, water, methanol, ethanol,isopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone,methyl formate, ethyl acetate, and mixtures thereof. Examples ofinitiators, if present, include hydrogen peroxide, alkylhydroperoxidesuch as t-butyl hydroperoxide and t-amyl hydroperoxide, dialkylperoxides such as di-t-butyl peroxide, peracids, peresters,percarbonates, persulfates, ketone peroxides such as methyl ethyl ketoneperoxide, oxygen, azo initiators and mixtures thereof.

In cases where the functional groups are generated by at least onepost-oligomerization reaction, such a post-oligomerization reaction iscarried out under a functional-group-generation condition which is knownto those skilled in the art. Such post-oligomerization reactionsinclude, but are not necessarily limited to hydrolysis, esterification,trans-esterification and epoxide ring-opening reaction. The reaction maybe carried out in a solvent and/or in the presence of a catalyst. Forexample, in a hydrolysis, esterification, or trans-esterificationreaction, an acid catalyst or a base catalyst is typically used.

The reaction between the functional group of the oligomer and thereactive moiety of a modifier is carried out under a second conditionwhich depends on the functional group, the reactive moiety, the solvent(if present), and other physical and chemical properties of the oligomerand the modifier. The second condition comprises a temperature in therange of from 0° C. to 450° C. and a residence time in the range of from0.1 second to 120 hours. Pressure is generally not a critical parameterunless the modifier has a relatively high vapor pressure at the reactiontemperature. Accordingly, a wide range of pressure may be used. Ambienttemperature is most convenient for most such reactions. If needed, apressure in the range of from 1 kPa (about 0.01 bar) to 35 MPa (350bars) maybe used. To the extent that such reactions conditions aredisclosed in U.S. Pat. No. 4,059,616, U.S. Pat. No. 4,133,793, and U.S.Pat. No. 4,208,313, they are incorporated herein by reference.

This reaction between a functional group and a reactive moiety may beconveniently carried out in air if there are no substantial sidereactions or by-product productions. Sometimes air or oxygen need bepresent in order to allow certain inhibitors such as hydroquinone to beused effectively. Optionally, a different non-reactive atmosphere may beused, particularly if air may interfere with reaction and/or cause anyof the components to decompose or deteriorate. Examples of gases forproviding such non-reacting atmosphere include, but are not necessarilylimited to nitrogen, argon, helium or mixtures thereof. Gases likecarbon dioxide also may be used alone or in conjunction with thenon-reacting atmosphere described above if such gases do not interferewith the reaction and/or cause any of the components to decompose ordeteriorate.

Unlike prior art products, the oligomers prepared in accordance with theprocess of the present invention are usually terminally unsaturated. Ifdesired, the unsaturated terminals may be subjected to further reactionssuch as hydrogenation, epoxidation, or a number of other additionreactions known in the art.

A modifier suitable for the present invention depends on the nature ofthe functional group. They are described below in more detail.Generally, the modifier must have at least one reactive moiety whichwill react with the functional group. Another requirement of a suitablemodifier is that it must have a crosslinkable group selected from thegroup consisting of carbon-carbon double bond (C═C), anoxygen-containing heterocyclic group, and mixtures thereof, wherein thecrosslinkable group remains pendant or substantially unreacted after thereaction between the modifier and the oligomer through the reactivemoiety and the functional group respectively.

Examples of a reactive moiety in a suitable modifier include, but arenot necessarily limited to C—OH [hydroxyalkyl group], —C(═O)OH,—C(═O)OR, —C(═O)X, oxygen-containing heterocyclic group and mixturesthereof. R is selected from a C₁ to C₁₅ alkyl group or an aryl group.Examples include, but are not necessarily limited to methyl, ethyl,n-propyl, n-butyl, 2-ethylhexyl, phenyl, and mixtures thereof. X isselected from the group consisting of chloride, bromide, and iodide.Examples of an oxygen-containing heterocyclic group include oxiranyl,oxetanyl and 1,3-dioxolanyl groups of the following formula:

R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are independently selected from thegroup consisting of H and C₁-C₈ alkyl groups. H is preferred for all ofthe “R” groups. It is also preferred to have two of R¹, R² and R³ as H,and the other, CH₃.

Examples of a modifier include, but are not necessarily limited to,glycidyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate,2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropylmethacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate,cinnamic acid, methylcinnamic acid, acrylic acid, methacrylic acid,crotonic acid, methyl acrylate, methyl methacrylate, methyl crotonate,ethyl acrylate, ethyl methacrylate, ethyl crotonate, n-propyl acrylate,n-propyl methacrylate, n-propyl crotonate, n-butyl acrylate, n-butylmethacrylate, n-butyl crotonate, 2-ethylhexyl acrylate, 2-ethylhexylmethacrylate, 2-ethylhexyl crotonate, acryloyl chloride, methacryloylchloride, crotonyl chloride, and mixtures thereof, provided that therespective modifies are chemically compatible with each other in themixtures.

The following reactions between the oligomer and the modifier are withinthe scope of the present invention whether the functional groups arepresent in the monomer A prior to the oligomerization or they aregenerated post-oligomerization from either the “monomer A equivalent” orthe monomer B units incorporated in the oligomer backbone structure.

I. When the functional group is hydroxy (—OH) groups, the reactivemoieties of the modifier are selected from the group consisting ofethylenically unsaturated carboxylic acids, esters of the ethylenicallyunsaturated carboxylic acids, acyl halide derivatives of theethylenically unsaturated carboxylic acids, and mixtures thereof.Examples of a monomer A in this group include, but are not necessarilylimited to allyl alcohol, 2-hydroxyethyl acrylate, 2-hydroxyethylmethacrylate, 2-hydroxyethyl crotonate, 3-hydroxypropyl acrylate,3-hydroxypropyl methacrylate, 3-hydroxypropyl crotonate, 4-hydroxybutylacrylate, 4-hydroxybutyl methacrylate, 4-hydroxybutyl crotonate andmixtures thereof. Examples of monomer A equivalent include allylacetate, allyl propionate, and vinyl acetate. Examples of a modifierinclude, but are not necessarily limited to, acrylic acid, methacrylicacid, crotonic acid, maleic acid, fumaric acid, itaconic acid,citraconic acid, cinnamic acid, methylcinnamic acid, methyl acrylate,methyl methacrylate, methyl crotonate, ethyl acrylate, ethylmethacrylate, ethyl crotonate, n-propyl acrylate, n-propyl methacrylate,n-propyl crotonate, i-propyl acrylate, i-propyl methacrylate, i-propylcrotonate, n-butyl acrylate, n-butyl methacrylate, n-butyl crotonate,2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl crotonateand mixtures thereof, acryloyl chloride, methacryloyl chloride, crotonylchloride, methacrylic anhydride and mixtures thereof.

II. When the functional group is selected from the group consisting ofepoxide (oxiranyl) and carbon-carbon double bond; and the modifiersconsist essentially of a compound selected from an ethylenicallyunsaturated carboxylic acid or their mixtures, and an ethylenicallyunsaturated alcohol or their mixtures. Examples of a monomer A in thisgroup are 1,3-butadiene 1,2 epoxide, glycidyl acrylate, glycidylmethacrylate, glycidyl crotonate, 1-vinyl-4-cyclohexene epoxide,1,3-butadiene, isoprene, 1-vinyl-4-cyclohexene, norbornadiene, andmixtures thereof. Examples of a modifier include acrylic acid,methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconicacid, citraconic acid, cinnamic acid, methylcinnamic acid and mixturesthereof Other suitable modifiers include 2-hydroxyethyl acrylate,2-hydroxyethyl methacrylate, 2-hydroxyethyl crotonate, 3-hydroxypropylacrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropyl crotonate,4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 4-hydroxybutylcrotonate and mixtures thereof Methylolacrylamide also may be used as amodifier.

III. V When the functional group is selected from the group consistingof anhydride, alkoxysilyl, and mixtures thereof, the modifier isselected from the group consisting of hydroxyalkyl esters ofethylenically unsaturated carboxylic acids and mixtures thereof.Examples of the monomer A in this group include, but are not necessarilylimited to maleic anhydride, itaconic anhydride, citraconic anhydride,γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane,vinyltrimethoxysilane, vinyltrichlorosilane, allyltriethoxysilane,allyltrichlorosilane, vinyl crotonate and mixtures thereof. Examples ofmodifiers include, but are not necessarily limited to 2-hydroxyethylacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl crotonate,3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropylcrotonate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate,4-hydroxybutyl crotonate, and mixtures thereof.

IV. When the functional group is selected from the group consisting ofhydroxyl (COH), carboxyl (COOH), amino (NH₂), and substituted amino (NHRor NR′R″) groups, the reactive moiety of a modifier consists essentiallyof an oxiranyl group. Examples of a preferred monomer A is selected fromthe group consisting of dimethylaminoethyl methacrylate,dimethylaminoethyl acrylate, and mixtures thereof. Examples of such amodifier include glycidyl acrylate, glycidyl methacrylate and glycidylcrotonate.

V. When the functional group is selected from the group consisting of ananhydride group, the reactive moiety of a suitable modifier may be anoxiranyl group. Examples of a monomer A include maleic anhydride,citraconic anhydride, itaconic anhydride, and mixtures thereof. Examplesof a suitable modifier include glycidyl acrylate, glycidyl methacrylate,glycidyl crotonate, and mixtures thereof.

VI. When the functional group is selected from the group consisting ofan aldehyde, a ketone group, the reactive moiety in a suitable modifieris preferred to contain a hydroxyalkyl group. Examples of the monomer Ainclude acrolein, methacrolein, methyl vinyl ketone, and mixturesthereof. Examples of a suitable modifier include 2-hydroxyethylacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl crotonate,3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropylcrotonate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate,4-hydroxybutyl crotonate and mixtures thereof.

VII. When the functional group is a vinyl group as part of an ester, noreaction with a reactive moiety is needed when the curing method isselected from electromagnetic irradiations. Examples of monomer Ainclude, but are not necessarily limited to vinyl acrylate, vinylmethacrylate, vinyl crotonate, and mixtures thereof. Examples of monomerB include, but are not necessarily limited to ethylene, propylene, C₄ toC₁₀ α-olefins, butadiene, isoprene, styrene, substituted styrene such asp-methylstyrene, vinyl ester, vinyl ether, vinyl silane such asvinyltrimethylsilane, vinyl halide, acrylic acid, methacrylic acid,crotonic acid, alkyl acrylate or methacrylate, or crotonate ester suchas methyl acrylate, methyl methacrylate, methyl crotonate, ethylacrylate, ethyl methacrylate, ethyl crotonate, n-propyl acrylate,n-propyl methacrylate, n-propyl crotonate, n-butyl acrylate, n-butylmethacrylate, n-butyl crotonate, and mixtures thereof., acrylamide,methacrylamide, N-substituted acrylamide, N-substituted methacrylamideand mixtures.

VIII. When monomer A is selected from vinyl chloride, vinyl bromide,vinyl acetate, vinyl benzoate, vinylidene halide (such as chloride orfluoride) and mixtures thereof, the modifier comprises a metal salt ofan unsaturated acid or a mixture of such salts. Examples of suchunsaturated acids include acrylic acid, methacrylic acid, crotonic acid,maleic acid, fumaric acid, itaconic acid, citraconic acid, cinnamicacid, methylcinnamic acid and mixtures thereof. The metal (ion) isselected from the group consisting of metals selected from the GroupsIA(Li, Na, K, Rb, Cs), IIA (Be, Mg, Ca, Sr, Ba), IIIA(Al. Ga, In, Tl)and mixtures of the period table. (see inside front cover of CRCHandbook of Chemistry and Physics, 76th Ed. 1995-1996, D. R. Lide,Editor-in-Chief CRC Press, Inc. 1995) Examples of such a salt include,but are not necessarily limited to lithium acrylate, lithiummethacrylate, lithium crotonate, sodium acrylate, sodium methacrylate,sodium crotonate, potassium acrylate, potassium methacrylate, potassiumcrotonate, rubidium acrylate, rubidium methacrylate, rubidium crotonate,cesium acrylate, cesium methacrylate, cesium crotonate, magnesiumacrylate, magnesium methacrylate, magnesium crotonate, aluminumacrylate, aluminum methacrylate and mixtures thereof. It is preferred touse phase transfer catalysis (PTC) in this case to achieve reasonablereaction rates. PTC can be effected by choosing an appropriate phasetransfer catalyst(s). Depending on the catalyst selected, the amount ofa phase transfer catalyst used is, based on the total moles of themodifier present, in the range of from 0 mol % to 50 mol %, preferablyin the range of from 0.001 mol % to 25 mol %, most preferably in therange of from 0.01 mol % to 20 mol %.

Typical phase transfer catalysts include, but are not limited to,quaternary ammonium, phosphonium, arsonium, antimonium, bismuthonium,and tertiary sulfonium salts, crown ethers. For the salts, examples ofsuitable counter ions include, but are not necessarily limited to,hydroxide, halide, sulfate, bisulfate, phosphate, nitrate, and mixturesthereof Examples of such catalysts include tetra-n-butylammoniumbromide, tetra-n-butylammonium chloride, tetra-n-butylammonium iodide,tetra-n-butylammonium bisulfate, tetra-n-butylammonium hydroxide,tetraethylammonium bromide, tetramethylammonium bromide,tetra-n-propylammonium bromide, monomethyl, trioctylammonium chloride[Aliquat 336] benzyl triethylammonium bromide, hexyl triethylammoniumbromide, octyl triethylammonium bromide, cetyl trimethylammoniumbromide, tricaprylylmethylammonium bromide, phenyl trimethylammoniumbromide, tetraphenylphosphonium bromide, triphenylmethylphosphoniumbromide, tetrabutylphosphonium bromide, tetraphenylarsonium bromide,pyridyl-butyl bromide, cetylpyridinium bromide, dicyclohexano-18-crown-6ether; 18-crown-6 and mixtures thereof A reference in the area is PhaseTransfer Catalysis Fundamentals, Applications, and IndustrialPerspectives, by C. Starks, C. Liotta, and M. Halpern, Chapman & Hall,New York, (1994). “Aliquat” is a registered trademark of General Mill,Inc.

IX: When the functional group in monomer A is an epoxide (oxiranyl)group, examples of a monomer A include glycidyl acrylate, glycidylmethacrylate, glycidyl crotonate, monoglycidyl maleate, monoglycidylfumarate, and mixtures thereof. Examples of monomer B include, but arenot necessarily limited to, ethylene, butadiene, isoprene, styrene,p-methylstyrene, methyl acrylate, methyl methacrylate, methyl crotonate,ethyl acrylate, ethyl methacrylate, ethyl crotonate, n-propyl acrylate,n-propyl methacrylate, n-propyl crotonate, n-butyl acrylate, n-butylmethacrylate, n-butyl crotonate, 2-ethylhexyl acrylate, 2-ethylhexylmethacrylate, 2-ethylhexyl crotonate, a vinyl ester such as vinylacetate, a vinyl ether such as vinyl ethyl ether, vinyl n-propyl ether,vinyl n-butyl ether, vinyl silane such as vinyltrimethylsilane andmixtures thereof. The curing method is selected from the groupconsisting of acid cure, base cure, generation of acid by anelectromagnetic irradiation selected from the group consisting ofultraviolet, visible light, X-ray irradiation, and y irradiation andcombinations thereof to produce a cured product from the radiationcurable composition.

Preferred oligomer compositions (monomer A and monomer B) and thecorresponding modifiers include, but are not necessarily limited to,those listed in the following Table 1:

TABLE 1 monomer A Group (monomer A equivalent)^(a) monomer B^(b)modifier^(c) II GA BA AA, MAA, or AOPA II GMA BA AA, MAA, or AOPA II GMAEA AA, MAA, or AOPA I HEA BA AA, MAA, or AOPA III MAN BE HEA or HEMA IVHEA EA ICEMA II IP BA AA II BD BA AA IV AA BA GMA III VTMO BA HEA orHEMA I^(d) VOH (VAc) BA AA or AOPA IV HBA BA GMA or GA IV HBA MMA GMA orGA I HEA BA MA or MMA I HBA BA AA, MAA, or AOPA ^(a)monomer equivalentsare in parentheses; AA: acrylic acid; GA: glycidyl acrylate; GMA:glycidyl methacrylate; BD: butadiene; IP: isoprene; MAA: methacrylicacid; HBA: 4-hydroxybutyl acrylate; HEA: 2-hydroxyethyl acrylate; MMA:methyl methacrylate; MA methyl acrylate; VOH: vinyl alcohol; VAc: vinylacetate; VTMO: vinyltrimethoxy silane; MAN: maleic anhydride. ^(b)BA:n-butyl acrylate; BVE: n-butyl vinyl ether; MMA: methyl methacrylate^(c)AA: acrylic acid; GA: glycidyl acrylate; GMA: glycidyl methacrylate;HEA: 2-hydroxyethyl acrylate; AOPA: acrylopropionic acid; ICEMA:isocyanatoethyl methacrylate. ^(d)After the acetate group is hydrolyzed.

It is also within the scope of the present invention that the oligomers,after reaction with the modifier, may be dispersed or emulsified in asolvent consisting essentially of water to form a waterborne formulationwhich can be used and cured, provided that there is a reasonablechemical and physical stability of the composition in such a waterborneformulation. It is generally required to have a surfactant in theformulation. Many surfactants known to those skilled in the art may beused, including but not limited to anionic surfactants, cationicsurfactants, amphoteric surfactants and nonionic surfactants. Somespecific examples include Triton X-100 and Triton X-200. (“Triton” is aregistered trademark owned by Union Carbide Chemicals & PlasticsTechnology Corporation.)

The terms “curable” and “crosslinkable” are used interchangeably hereinto mean that a pendant double bond or oxygen-containing heterocyclicgroup can be further reacted/crosslinked under a set of suitableconditions and in the presence of one parameter selected from the groupconsisting of a catalyst, an energy source, a free radical source, anacid, a base, or a combination thereof. The curable composition may becured (crosslinked) by a number of methods. Examples of such methodsinclude, but are not necessarily limited to electromagnetic irradiationsuch as UV irradiation(UV), visible light irradiation(VIS), γirradiation, and X-ray irradiation(X-ray), electron beam irradiation(E-beam), chemical or thermal generation of free radicals,electrochemical generation of free radicals, photochemical generation offree radicals and combinations thereof. For E-beam and/orelectromagnetic irradiations such as UV/VIS irradiation as the curingmethod(s), the curable composition may further comprise one or morephotoinitiators as an additive(s) which function as free-radicalinitiator(s), cationic initiator(s), or anionic initiator(s). A generalreference for photo free-radical generations and photoinitiators can befound in Chapter 5 of “Photogeneration Of Reactive Species For UVCuring” by C. Roffey, John Wiley & Sons, New York, N.Y. (1997). To theextent the reference discloses various suitable photoinitiators and/orphoto free-radical generations, it is incorporated herein by reference.

Acids or electromagnetic irradiation (such as UV and/or VIS irradiation)for generating acids or bases may be used for curing a compositionhaving oxygen-containing heterocyclic groups such as oxiranyl, oxetanylor 1,3-dioxolanyl groups. E-beam, UV and/or VIS irradiation(s) are threeof the preferred curing methods.

The curable compositions, particularly may further comprise one or morediluent monomers as another additive, with or without one or morephotoinitiators. Such a diluent monomer(s) may or may not be the same asone or more of the monomers which are already incorporated into thebackbone of the oligomer(s). Many monomers or their mixtures used toform the oligomer(s) may serve the function as a “diluent monomer(s).” Adiluent monomer may serve to reduce viscosity, provide solvency, and/orprovide additional desired properties to the final cured product,particularly for producing an electromagnetic irradiation cured product.A general reference of such diluent monomers or sometimes referred to asreactive monomers in the curing composition can be found in Chapter 6 of“Photogeneration Of Reactive Species For UV Curing” by C. Roffey, JohnWiley & Sons, New York, N.Y. (1997).

Table 2 provides a simplified general guideline for selecting thevarious components:

TABLE 2 Curing method Required^(a) Optional^(b) EB, X-ray or γ-ray —monomers UV or VIS photo initiators monomers (radical; photoacid;photobase) free radical free radical sources monomers (thermal orchemical) acid or base acid or base sources monomers ^(a)Oligomers arerequired for all the methods. ^(b)See text for the definition of“monomers” (diluent monomers)

Generally, a UV source has a wavelength in the range of from 180 nm to400 nm. A visible light (VIS) source has a wavelength in the range offrom 400 nm to 700 nm. Information regarding EB may be found inRadiation Curing In Polymer Science and Technology—Volume I, ed. J. P.Fouassier and J. F. Rabek, Elsevier Applied Science, New York, 1993Information regarding photoacids may be found in Radiation Curing InPolymer Science and Technology—Volume II, ed. J. P. Fouassier and J. F.Rabek, Elsevier Applied Science, New York, 1993 and in Prog. Polym.Sci., Vol. 21, pp 1-45, 1996.

For all the reactions involved in the process discussed herein, it isunderstood that they can be carried out individually in a continuousmode, a semi-continuous mode, a batch mode, a continuously stirred tankreactor mode, or a combination thereof. The various stages of theprocess may be carried out in the same reactor or different reactors. Itis preferred to carry out the oligomerization reaction in a continuousmode. The reactor geometry and/or the residence time may be adjusted toprovide different flow regimes for controlling the product yield,product composition and/or product properties. Such information isavailable in many references. One such reference is U.S. Pat. No.5,710,227 (supra). Alternately, some of the reactions may be carried outsimultaneously in a continuous mode, a semi-continuous mode, a batchmode, a continuously stirred tank reactor mode, or a combinationthereof.

While it is generally preferred to recover the product from eachindividual reaction of the process prior to conducting the nextreaction, the present invention also will work with minimum or norecovery or no purification. For example, it is not required torecover/separate the oligomers prior to reacting with a modifier toproduce the curable compositions, or carrying out thepost-oligomerization generation of functional groups. In a case wherethe monomers and the modifier in the feed at the same time, there is noneed for any intermediate purification or separation. Typical recoveryor purification methods include, but not necessarily limited todistillation, extraction, filtration, centrifugation, sedimentation,solvent removal, residual monomer removal, residual modifier removal,catalyst removal and combinations thereof.

The present invention further relates to a curable composition preparedin accordance with the disclosed process. In particular the curablecomposition comprises of an oligomer having a Dp in the range of from 3to 100 which has reacted with a modifier after the oligomer is formed,wherein the oligomer is prepared from a monomer A and monomer B. Thecomposition may further comprise a free monomer selected from any of themonomers disclosed herein. The free monomer may or may not be the sameas either the monomer A or the monomer B in the oligomer.

Preferably, the curable composition consists essentially of (a) anoligomer having a Dp in the range of from 3 to 100 which has reactedwith a modifier after the oligomer is formed, wherein the oligomer isprepared from a monomer A and monomer B, (b) a free monomer selectedfrom any of the monomers disclosed herein, (c) an initiator, . The freemonomer may or may not be the same as either the monomer A or themonomer B in the oligomer.

The following examples are intended for illustration purposes only. Theyshould not be interpreted to limit the scope or spirit of the presentinvention which is solely defined by the claims and the specificationdisclosed herein.

EXAMPLE I Oligomerization

An oligomer of the present invention may be prepared in accordance withthe following procedure.

A 10-foot (3.3 meters) long section of stainless tubing having an innerdiameter of one-sixteenth inch (1.6 mm) and wall thickness of 0.050 inch(1.27 mm) was connected at one end to a high pressure pump (HewlettPackard Model HP 1050 TI) and at the other end to a back-pressurecontrol device. Between the two ends, the section of tubing was coiledabout a torus-shaped metal mandrel. The mandrel was situated above aprimary coil of a transformer so that the coils of tubing and themandrel functioned as secondary coils of the transformer. The coils oftubing were further equipped with one end of a temperature probe. Theother end of the temperature probe was connected to a temperaturecontrolling device. The temperature controlling device regulated thecurrent supplied to the primary coil of the transformer which had theeffect of regulating the heat of inductance imparted to the coiled steeltubing.

A mixture of a monomer A and a monomer B (a few specific examples areshown below in the Table 3) was used in the oligomer synthesis reaction.The mixture may further comprise an initiator and optionally a solvent.Nitrogen was bubbled through the mixture while stirring. If a solventwas not used, the initiator and monomers were separately fed into thereactor.

In a typical experiment, a suitable solvent was pumped into and throughthe tubing via the high pressure pump at a certain preset rate in therange of from about 0.05 to about 10 milliliters per minute (ml/min).The pressure was maintained at a level of from 20 MPa (200 bars) to 35MPa (350 bars). Electric current was supplied to the primary coil of thetransformer to increase the temperature within the tubing to the desiredoligomerization temperature. The current was then adjusted to maintainthat temperature for the oligomerization reaction. After about 15minutes, the solvent being pumped through the tubing was replaced by thereaction mixture which as continuously pumped through the tubing at thesame preset rate while maintaining the desired temperature and pressure.After an amount of time has elapsed for the solvent to be totallyreplaced from the inside of the tubing, the effluent from theback-pressure control device was collected as the product. After thesupplies of the mixture, or individual monomers, were used up, a solventwas pumped through the tubing at the same present rate, temperature, andpressure. Any solvent and/or residual monomers were removed from theproduct on a rotary evaporator.

The products in Table 3 were analyzed by various analyticalmethods—molecular weights by gel permeation chromatography (GPC);structure and co-monomer ratio by proton and carbon NMR spectroscopies;and end-groups by NMR or matrix-assisted laser desorption massspectrometry (MALDI-MS).

TABLE 3 Oligomer# Monomer A* Monomer B* Mw Mn A 2.6 HBA 5.6 BA 2130 1091B 3.2 HEA 5.4 BA 2302 1064 C 2.5 GA 6.0 BA 2245 1083 D 2.5 GMA 5.4 BA2250 1144 E 2.5 HEA 6.0 BA 5350 2384 #: Dp's are: A: 8.2; B: 8.6; C:8.5; D: 7.9; E: 8.5 *: Average number of monomer units per oligomer.HBA: 4-hydroxy butyl acrylate; HEA: hydroxyethyl acrylate; GA: glycidylacrylate; GMA: glycidyl methacrylate; BA: n-butyl acrylate.

EXAMPLE II Reaction of a Modifier with an Oligomer

The equipment used was a 250 ml three-neck round bottom flask outfittedwith a reflux condenser, an overhead stirrer, a gas inlet tube and athermocouple. The flask was charged with (a) 137.06 grams of an oligomerhaving a composition of 38:62 (mole %) of GMA (glycidyl methacrylate,monomer A) to EA (ethyl acrylate, monomer B), a Dp of 6.5 and 23,000 ppmresidual GMA, (b) 40.0 grams acrylic acid, (c) 0.2 grams of CordovaAccelerator AMC-2 (chromium 2-ethylhexanoate), and (d) 0.26 grams of a10%(weight) solution of Actrene [registered trademark of ExxonCorporation] in propylene glycol methyl ethyl ether.

The mixture in the flask was stirred and heated under dry nitrogen to90° C. for 6 hours. No GMA residuals were detected after this period.The reflux condenser was then replaced with a distillation head and anyunreacted AA was removed by distillation under reduced pressure with ahouse vacuum.

Other examples where the modifier was acrylic acid (AA) were:

TABLE 4 Product Monomer A* Monomer B* Modifier Mw Mn A2 2.6 HBA 5.6 BA2.5 AA 3567 1350 B2 3.2 HEA 5.4 BA 3.1 AA 5124 1740 C2 2.5 GA 6.0 BA 2.5AA 2719 1385 D2 2.5 GMA 5.4 BA 2.5 AA 2614 1279 *: Average number ofmonomer units per oligomer. HBA: 4-hydroxy butyl acrylate; HEA:hydroxyethyl acrylate; GA: glycidyl acrylate; GMA: glycidylmethacrylate; BA: n-butyl acrylate. #: Dp: A2, 8.2; B2, 8.6; C2: 8.5;D2: 7.9.

EXAMPLE III Reaction of a Modifier with an Oligomer

The equipment used was a 100 ml three-neck round bottom flask outfittedwith a reflux condenser, an magnetic stirring bar, an air inlet tube anda thermocouple. The flask was charged with 41.1 grams of an oligomerhaving a composition of 20:80 (mole %) of AA (acrylic acid, monomer A)to BA (n-butyl acrylate, monomer B) and Mn of 1204. With stirring, theflask and the oligomer were heated to about 100° C. under a dry airpurge over a period of 15 minutes. The mixture was cooled to roomtemperature over a 30 minute period under a dry air purge, followed byaddition of 16.31 grams of GMA, 20 grams ethyl acetate and 0.06 grams ofCordova Accelerator AMC-2 (chromium 2-ethylhexanoate). While stirringunder a dry air purge, the mixture was heated to about 85° C. for fivehours. It was then cooled to room temperature. Residual GMA was found tobe 2300 ppm.

A portion of 0.25 g of 2-(ethylamino)ethanol was added to the flask andthe mixture was heated to 65° C. over 20 minutes, cooled to roomtemperature and let stand for 4 days. Residual GMA was found to be 150ppm. To this were added 20.0 grams acetic acid and 10.0 grams of ethylacetate. The mixture was heated to 80° C. for 8 hours. No residual GMAwas detected after this period. The reflux condenser was then replacedwith a distillation head. Residual acetic acid and ethyl acetate weredistilled off under reduced pressure to produce the desired product.

EXAMPLE IV Reaction of Modifier with Oligomer

The equipment used was a 250 ml pear-shaped flask outfitted with amagnetic stirring bar and a drying tube. The flask was charged with (a)25 grams of an oligomer having a composition of 1:2 (mole ratio) of HEA(monomer A) to EA (monomer B); (b) 50 ml THF; and (c) 12.2 grams ofisocyanatoethyl methacrylate (ICEMA). A 0.05g dibutyltin dilauratecatalyst was added to this mixture at 25° C. The mixture was thenstirred at 25° C. for two days. An additional 0.45 g of the samecatalyst was added and the mixture was heated in an oil bath to 50° C.for 4 days. At this time, it was determined that all the isocyanategroups have been converted to urethane groups. The product wasconcentrated by removing volatiles with a rotary evaporator. The productwas characterized by Fourier transform infrared spectroscopy (FTIR);C-13 nuclear magnetic resonance (NMR); 2-dimensional NMR, and MALDI-MS.The glass transition temperature (Tg) and viscosity of the liquidproduct were −73° C. and 16,000 MPa-sec (cps, Brookfield viscometer at25° C.) respectively.

EXAMPLE V Reaction of Modifier with Oligomer

The following are other examples. Reactions 1-4 were carried out neat,and reactions 5-10, in refluxing toluene with azeotropic removal ofwater. The reaction mixture also contained inhibitors: 1.4-hydroxy-2,2,6,6,-tetramethylpiperidinyloxy (HTEMPO, 500 ppm); 2:butylhydroxytoluene (BHT, 1000 ppm)/air; 3: HTEMPO (500 ppm); 4: HTEMPO(500 ppm); 5: BHT 1000 ppm)/air; 6: hydroquinone(1000 ppm)/air; 7:HTEMPO (500 ppm); 8: HTEMPO (500 ppm); 9: HTEMPO (500 ppm); 10: HTEMPO(500 ppm).

TABLE 5 No. oligomer^(a) modifier^(b) catalyst^(c) time (h) temp (° C.)conv^(d) conv^(e) Mw/Mn 1 P1 AA Cr 1.5 100 97% 96% 4015/1517 2 P1 AA Cr1.5 100 91% 95% 4075/1494 3 P1 AA Cr 1.5 100 100%  97% 2884/1466 4 P1 AACr 2.5 100 98% 94% 2719/1385 5 P2 AA MSA^(f) 3.5 g 97% h 3600/1515 6 P3AA MSA^(f) 6.5 g 93-100% h 3728/1148 7 P2 AA AM 2.5 g 88 h 4217/1285 8P2 AA AM 2.5 g 93 h 5644/1760 9 P2 AA AM 2.5 g 93 h 4734/1383 10 P2 AAAM 2.5 g 100  h 3294/1291 ^(a)P1: 6.0 n-butyl acrylate/2.5 glycidylacrylate (mole ratio); M_(w)/M_(n) = 2245/1083; Dp = 8.5 P2: 5.6 n-butylacrylate/2.6 4-hydroxybutyl acrylate (mole ratio); M_(w)/M_(n) =2130/1091; Dp = 8.0 P3: 4.8 n-butyl acrylate/2.4 4-hydroxybutyl acrylate(mole ratio); M_(w)/M_(n) = 1965/969; Dp = 7.2 ^(b)AA: acrylic acid;AOPA: acrylopropionic acid ^(c)Cr: chromium 2-ethylhexanoate, 0.1 wt %based on total weight of reaction mixture, ˜100 ppm Cr. MSA:methanesulfonic acid; for runs 5, 6, and 7, 2 mol % of MSA, based on HBAin the oligomer was used. AM: Amberlyst 15 [Amberlyst is a registeredtrademark of Rohm and Haas Company] ^(d)Conversion of functional groupon the oligomer. ^(e)Conversion of reactive moiety on the modifier.^(f)40 mole % concentration. ^(g)Refluxing toluene temperature. ^(h)Notmeasured.

These examples showed that oligomers could be reacted with modifiers toform products of this invention.

EXAMPLE VI UV Curing

An oligomer, either neat, or formulated, was applied to the surface of asubstrate by using a wet film applicator to form a film with 2 mil(5.1×10⁻³ cm) thickness. The film applicator used was an Eight-Path WetFilm Applicator from Paul N. Gardner Company, Inc. Substrates includeglass, aluminum, and cold rolled steel.

The coated surfaces were then cured, in air or nitrogen, with an RPCModel 1202 UV processor equipped with two 200 watts/inch (80 watts/cm)medium pressure mercury arc lamps at a belt speed of 20 to 100 feet (6to 30 meters) per minute. The table below represents the typicalenergy/area at various belt speeds, measured by using a CompactRadiometer (UV Process Supply Inc.).

TABLE 6 Speed (feet/min; [meters/min]) Energy/Area (mJoule/cm²) 20 [6]2400  40 [12] 1200  60 [18]  780  80 [24]  620 100 [30]  500

The following Table 7 shows curing results obtained with neat product inthe presence of 2 wt % Darocure 1173 obtained from Ciba SpecialtyChemicals.

TABLE 7 Swell Soluble Cure Conditions Product Ratio^(a) Fraction^(b) (%)no of passes/speed/atmosphere A2 3.3 35  3/50 ft/min/air B2 2.1 15  4/50ft/min/nitrogen B2 2.0 13  1/20 ft/min/nitrogen B2 1.7 5 2/20ft/min/nitrogen C2 1.6 9 6/50 ft/min/nitrogen D2 1.8 9 6/50ft/min/nitrogen E2 1.1 0 3/50 ft/min/nitrogen ^(a)determined by theratio of the wet sample weight to the final dry sample weight intetrahydrofuran (THF). ^(b){(initial sample weight—final dry sampleweight)/initial sample weight} X 100% in THF.

The following Table 8 shows curing results with product B2 in thepresence of different amounts of a monomer TMPTA (and 2 wt % Darocure1173 obtained from Ciba specialty chemicals).

TABLE 8 B2 TMPTA Swell Soluble Cure Conditions* wt % wt % Ratio Fraction(%) no of passes/speed 100   0 2.0 13  1/20 ft/min 75 25 1.2 3 1/20ft/min 50 50 1.1 0 1/20 ft/min *under nitrogen

These examples showed that curable compositions prepared in accordancewith the present invention could be cured under a variety of conditions.

It is claimed:
 1. A process of preparing a curable compositioncomprising the steps of: (a) forming an oligomer having a Dp in therange of from 3 to 100 by either: (i) oligomerizing a mixture comprisinga monomer A and a monomer B, wherein the monomer A has at least onefunctional group which remains substantially unreacted during theoligomerization process; or (ii) oligomerizing a mixture comprising amonomer A equivalent and a monomer B and generating the at least onefunctional group during or after the oligomerization process; whereinthe oligomer has a first number of monomer units incorporated into itsbackbone; and wherein the oligomerization process is conducted at atemperature in the range of from 150° C. to 650° C., a pressure in therange of from 3 MPa to 35 MPa which is sufficient to maintain themixture in a fluid state and a residence time in the range of from 0.1second to 1 minute; (b) reacting a modifier having at least one reactivemoiety with the oligomer through a reaction under a second conditionbetween the reactive moiety of the modifier and the functional groupincorporated into the oligomer to produce the curable composition,wherein the modifier further comprises a curable group selected from thegroup consisting of a carbon-carbon double bond, an oxygen-containingheterocyclic group and mixtures thereof, and the curable group remainspendant in the curable composition and crosslinkable after the reaction.2. A process of preparing a curable composition comprising the steps of:v(a) forming an oligomer having a Dp in the range of from 3 to 100 byeither: (i) oligomerizing a mixture comprising a monomer A and a monomerB, wherein the monomer A has at least one functional group which remainssubstantially unreacted during the oligomerization process; or (ii)oligomerizing a mixture comprising a monomer A equivalent and a monomerB and generating the at least one functional group during or after theoligomerization process; wherein the oligomer has a first number ofmonomer units incorporated into its backbone; and wherein theoligomerization process is conducted at a temperature in the range offrom 275° C. to 450° C., a pressure in the range of from 3 MPa to 35 MPawhich is sufficient to maintain the mixture in a fluid state and aresidence time in the range of from 0.1 second to 4 minutes; (b)reacting a modifier having at least one reactive moiety with theoligomer through a reaction under a second condition between thereactive moiety of the modifier and the functional group incorporatedinto the oligomer to produce the curable composition, wherein themodifier further comprises a curable group selected from the groupconsisting of a carbon-carbon double bond, an oxygen-containingheterocyclic group and mixtures thereof, and the curable group remainspendant in the curable composition and crosslinkable after the reaction.3. The process of claim 1, wherein said monomer B is selected from thegroup consisting of ethylene, propylene, C₄ to C₁₀ α-olefins, butadiene,isoprene, styrene, substituted styrene, vinyl ester, vinyl ether, vinylsilane, vinyl halide, acrylic acid, methacrylic acid, crotonic acid,alkyl acrylate ester, alkyl methacrylate ester, alkyl crotonate ester,acrylamide, methacrylamide, N-substituted acrylamide, N-substitutedmethacrylamide and mixtures thereof.
 4. The process of claim 1, whereinthe at least one functional group is selected from the group consistingof a hydroxyl group, a carboxylic acid group, a halide, an oxiranylgroup, an anhydride group, an ester, an alkoxysilyl group, and acarbon-carbon double bond.
 5. The process of claim 1, wherein themonomer A is selected from the group consisting of allyl alcohol, allylacetate, allyl propionate, allyl acrylate, allyl methacrylate, allylcrotonate, vinyl acrylate, vinyl methacrylate, vinyl crotonate1,3-butadiene, isoprene, glycidyl methacrylate, glycidyl acrylate,2-hydroxyehyl acrylate, 3-hydoxypropyl acrylate, 4-hydroxybutylacrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate,4-hydroxybutyl methacrylate, maleic anhydride, itaconic anhydride,citraconic anhydride, vinyltrimethoxysilane,γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane,vinyltrichlorosilane, allyltriethoxysilane, allytrichlorosilane, andmixtures thereof; and the monomer B is selected from the groupconsisting of acrylic acid, methacrylic acid, crotonic acid, maleicacid, fumaric acid, itaconic acid, citraconic acid, cinnamic acid,methylcinnamic acid, methyl acrylate, methyl methacrylate, ethylacrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate,i-propyl acrylate, i-propyl methacrylate, n-butyl acrylate, n-butylmethacrylate, sec-butyl acrylate, sec-butyl methacrylate and mixturesthereof.
 6. The process of claim 1, wherein the modifier is selectedfrom the group consisting of acrylic acid, methacrylic acid, crotonicacid, methyl acrylate, methyl methacrylate, methyl crotonate, ethylacrylate, ethyl methacrylate, ethyl crotonate, n-propyl acrylate,n-propyl methacrylate, n-propyl crotonate, i-propyl acrylate, i-propylmethacrylate, i-propyl crotonate, n-butyl acrylate, n-butylmethacrylate, n-butyl crotonate, acryloyl chloride, methacryloylchloride, crotonyl chloride, and mixtures thereof; and the monomer A isselected from the group consisting of allyl alcohol, allyl acetate,allyl propionate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,2-hydroxyethyl crotonate, 3-hydroxypropyl acrylate, 3-hydroxypropylmethacrylate, 3-hydroxypropyl crotonate, 4-hydroxybutyl acrylate,4-hydroxybutyl methacrylate, 4-hydroxybutyl crotonate, an oxiranyl, andmixtures thereof.
 7. The process of claim 2, wherein said monomer B isselected from the group consisting of ethylene, propylene, C₄ to C₁₀α-olefins, butadiene, isoprene, styrene, substituted styrene, vinylester, vinyl ether, vinyl silane, vinyl halide, acrylic acid,methacrylic acid, crotonic acid, alkyl acrylate ester, alkylmethacrylate ester, alkyl crotonate ester, acrylamide, methacrylamide,N-substituted acrylamide, N-substituted methacrylamide and mixturesthereof.
 8. The process of claim 2, wherein the at least one functionalgroup is selected from the group consisting of a hydroxyl group, acarboxylic acid group, a halide, an oxiranyl group, an anhydride group,an ester, an alkoxysilyl group, and a carbon-carbon double bond.
 9. Theprocess of claim 2, wherein the monomer A is selected from the groupconsisting of allyl alcohol, allyl acetate, allyl propionate, allylacrylate, allyl methacrylate, allyl crotonate, vinyl acrylate, vinylmethacrylate, vinyl crotonate, 1,3-butadiene, isoprene, glycidylmethacrylate, glycidyl acrylate, 2-hydroxyethyl acrylate,3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethylmethacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate,maleic anhydride, itaconic anhydride, citraconic anhydride,vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane,vinyltriethoxysilane, vinyltrichlorosilane, allyltriethoxysilane,allyltrichlorosilane, and mixtures thereof; and the monomer B isselected from the group consisting of acrylic acid, methacrylic acid,crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconicacid, cinnamic acid, methylcinnamic acid, methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate,n-propyl methacrylate, i-propyl acrylate, i-propyl methacrylate, n-butylacrylate, n-butyl methacrylate, sec-butyl acrylate, sec-butylmethacrylate and mixtures thereof.
 10. The process of claim 2 whereinthe modifier is selected from the group consisting of acrylic acid,methacrylic acid, crotonic acid, methyl acrylate, methyl methacrylate,methyl crotonate, ethyl acrylate, ethyl methacrylate, ethyl crotonate,n-propyl acrylate, n-propyl methacrylate, n-propyl crotonate, i-propylacrylate, i-propyl methacrylate, i-propyl crotonate, n-butyl acrylate,n-butyl methacrylate, n-butyl crotonate, acryloyl chloride, methacryloylchloride, crotonyl chloride, and mixtures thereof; and the monomer A isselected from the group consisting of allyl alcohol, allyl acetate,allyl propionate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,2-hydroxyethyl crotonate, 3-hydroxypropyl acrylate, 3-hydroxypropylmethacrylate, 3-hydroxypropyl crotonate, 4-hydroxybutyl acrylate,4-hydroxybutyl methacrylate, 4-hydroxybutyl crotonate, an oxiranyl, andmixtures thereof.